Detection of Food Preservatives and Dulcin by Thin Layer Chromatography

Abstract

Thin layer chromatography was applied ta the detection of benzoic, salicylic, dehydroacetic, and sorbic acids, ethyl, propyl and butyl esters af p-hydroxybenzoate and dulcin. Kieselgel G activated at 80°C for 30 minutes or Wakogel B-5 activated at 100°C for 30 minutes was used. For the detection of the spots, 1% ferric chloride solution, 0.1% bromcresolgreen alcohol solution and 1% potassium permanganate solution were successively sprayed. The chromatoplate was developed with chloroform-propionic acid (4: 1) mixture for the group separation of the esters, the acids and dulcin.Chloroform-ethyl acetate (9: 1) mixture was used for the separation of sorbic acid from benzoic acid and dehydroacetic acid, and also for the identification of esters (as p-hydroxybenzoic acid). The preservatives were clearly separated with n-heptane-propionic acid (4: 1) mixture, by which the good separation of dehydroacetic acid from benzoic acid and sorbic acid has been achieved.